A convicted sex offender has been arrested over the sexual assault of a boy who is under the age of 12.

The boy was attacked in a laneway in a Mayo town on Thursday of last week.

A suspect, aged in his early 70s, was arrested by investigating gardaí yesterday.

He was being held at Claremorris Garda Station in Co Mayo last night as officers continued their investigations into the incident.

Details of the distressing case only emerged yesterday, but it is understood the boy was lured to the laneway when the suspect allegedly offered him money after initially confronting the victim on the street.

The Irish Independent understands specialist garda interviewers spoke with the boy and took down a detailed account of the alleged incident.

Sources have described the alleged sex attacker as a "prolific sex offender" who previously served a lengthy sentence in the UK for sex abuse-related offences.

It has emerged he was jailed for six years in England in the mid-1990s for a sexual offence in which he abused a young boy in a hotel.

Shockingly, the Irish Independent has learnt the suspect has previous convictions for indecent assault offences committed in England dating from the 1960s. He also served a jail sentence in the 1980s.

After being jailed in the UK, the sex offender moved to Ireland and has been based here since 2001.

It has since emerged that he has lived in various locations around the country, including Dublin, Kerry, Galway and Donegal, as well as Mayo.

Sources have revealed that in some instances, the convicted abuser was forced to move from his temporary home after locals became aware of his past offences.

It is understood that gardaí are hopeful that they will be able to press charges in the Mayo case.

Questioning of the suspect continued yesterday.

Last month, the Central Statistics Office (CSO) released its recorded crime statistics for 2015, with the figures revealing a 15pc increase in the number of sexual offences recorded by gardaí.

Statistics show that recorded sexual offences rose from 2,053 in 2014 to 2,361 in 2015.

Sexual offences involving mentally impaired victims, aggravated sexual assaults and other sex crimes are also on the rise.